my personal favourite is Coda. I tried Textmate for a while but Coda is way more feature rich, although annoyingly it doesn't highlight braces in the way I'd like. Definitely worth the money. Sublime is apparently the next big thing, although it doesn't support 10.5 or lower. Get it while it's in beta! http://www.sublimetext.com/

There are many editors which I tried out, but non of them I had everything what is important to me. Except for 'Netbeans' which I still don't like, because of crappy laptop.

So right now I'm using 'Geany'.It loads fast, has a folding, line marking, compiling features.Folding is manual, you can't chose like "Fold all 3rd level folds" like in 'Notepad++', that's annoying, 'cause it was most useful feature to me. Especially since I'm working on new CMS which is based on OOP, it has large classesSecond feature would be text marking. Marks a text which contains same characters - not found on "Geany", but possible on many other editors.Third most important feature which I didn't find in any editor is CVS. Because of that I end up with using 'Netbeans' for that feature. There even aren't any others programs which would handle CVS well (with GUI, I haven't tried out ones which works on command lines)

What I liked most on 'Geany' is compiling, even thought it was most popular feature I found on most of Linux editors.

Conclusion:In the end, after comparing pros and cos I encountered. For programming Linux is a crap.It doesn't have any